There are numerous alternatives to conventional medications that can aid producers of chickens and poultry products through a nutrient-rich diet. Although there are many nutritional tools available in abundance today, among the most studied natural feed additives in poultry are yeast bio-actives and Spirulina platensis. Spirulina and yeast bio-actives are from different kingdoms.
One is from the algae family (Spirulina platensis), whereas the other is from the fungus family (Saccharomyces cerevisiae). Both of these microorganisms are present everywhere in this world as well as in our lives. Spirulina has been on this evolutionary journey through photosynthesis for more than 3.5 billion years (4 billion years for some scientists), whereas yeast bio-actives have been critical to human culture for many thousands of years.
What are Yeast Bio-Actives in Poultry Nutrition?
The yeast bioactive compounds are found in Saccharomyces cerevisiae (the organisms from which they come) which come from extracts of the yeast’s cell wall. Yeast-based products will have three main types based on this information and be of benefit to Poultry:
- beta-1,3/1,6-glucans that stimulate the innate immune response of the host
- mannan oligosaccharides which have prebiotic properties that can bind to and prevent pathogen entry into the host
- hydrolysed yeast/yeast culture which contain nucleotides, vitamins and other metabolites produced during fermentation.
MDPI Agriculture (2025) states that including yeast or yeast by-products will improve production, enhance immune response, influence gut microbiota and reduce oxidative stress of broilers, layers and breeders making it an excellent and diverse option for poultry natural antibiotics.
Spirulina in Poultry: Rapid Recap of Core Benefits
Spirulina platensis is a blue-green algae that contains 60% to 70% protein along with the essential amino acids (EAA), the protein-bound pigment phycocyanin, and carotenoids (the color pigments present in many fruits and vegetables).
The benefits related to growth performance, gut microbiota, antioxidant defense, and immune function that have been observed from feeding Spirulina (0.1% to 0.5% of diet) to poultry are as follows:
Growth Performance: An In-depth Study of the performance of growth by examining broiler chickens fed 0.1%-0.5% Spirulina revealed that Spirulina-fed broilers gained significantly more weight than broilers in the control group, in addition to achieving a lower feed conversion ratio (FCR) (BMC Vet Res 2024).
Gut Microbiota: In the examination of gut microflora, it was determined that the number of Lactobacillus spp. in the ceca of Spirulina-chickens was significantly increased, while the number of E. coli was significantly decreased (BMC Vet Res 2024).
Antioxidant Defense: An examination of antioxidant defense indicated that Spirulina- chickens had significantly greater levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase, as well as total antioxidant capacity (TAC), when compared to control chickens exposed to oxidative stress (Science Direct 2025).
Immune Function: An examination of immune function revealed that Spirulina-fed poultry expressed greater macrophage, NK cell, and antibody titers in response to NDV and AI vaccine antigens than the control group (Frontiers in Immunology, 2023). (Note to editor: Include appropriate references for using footnotes rather than parentheses.)
Yeast Beta-Glucan & MOS: What the Trials Show
Beta-glucans and MOS operate through distinct but complementary mechanisms to Spirulina’s bioactives:
- Binds to PAMP receptors on macrophages as well as dendritic cells, thereby providing the “trained” innate immune response.
- Boosts phagocytic activity on macrophages, generates fresh immunocytes to flow into lymphoid organs, as well as increases anti-inflammatory responses as per Frontiers in Veterinary Science, 2022.
- Improves morphology of gut by enhancing height of villus as well as depth of crypt under both normal as well as pathological conditions.
MOS (Mannan Oligosaccharides):
- Acts as a decoy receptor; pathogens such as Salmonella, E. coli and perfringens bind to the mannose receptors on MOS instead of attaching to the epithelial cells of the gut.
- Significantly increases the diversity of Lactobacillus community microscopically in the ileum and reduces the perfringens and E. coli counts, as indicated by numerous studies referenced in Veterinarni Medicina in 2025.
- Provides a net increase of 5.4% in average body weight gain and a 2% improvement in FCR of broilers through enhanced digestion and absorption, as cited by MDPI Agriculture in 2025.
Combining MOS and beta-glucan has been demonstrated to provide a measurable synergistic effect. For example, using the research done at Poultry Science by Teng and colleagues (2021) the combination was shown to provide significantly greater jejunum villus height, improved growth performance during the starter phase, and greater gut barrier integrity than did either ingredient alone. Thus, confirming the theory of dual-action when combining gut cleaning with gut immunity training.
Why Spirulina + Yeast Bio-Actives Is a Next-Gen Strategy
The reason these two categories work so well together is that they operate on different but reinforcing biological pathways:
|
Ingredient |
Primary Action |
Secondary Action |
|
Spirulina platensis |
Antioxidant + Immune activation |
Gut microbiota modulation |
|
Beta-glucan |
Innate immune training (macrophages) |
Gut morphology improvement |
|
MOS |
Pathogen exclusion (gut) |
Prebiotic gut microbiota support |
|
Yeast nucleotides |
Gut epithelial cell repair |
Immune cell proliferation support |
As per the Journal of Animal Science and Biotechnology (2024), “Synergistic effects of polysaccharides, like Enteromorpha polysaccharides, combined with yeast glycoprotein, significantly upregulated antioxidant gene expression and enzyme activities in broilers beyond the effects of single components.” The same applies to Spirulina and yeast bio-active combinations, each complementing each other where the other may not.
Optimal Inclusion Rates
|
Supplement |
Recommended Dose |
Key Benefit |
Source |
|
Spirulina platensis |
0.3–0.5% of diet |
Growth, FCR, gut microbiota, immunity |
BMC Vet Research, 2024 |
|
Beta-glucan |
0.002% of diet (2 mg/kg) |
Immune training, villus height |
Poultry Science, 2021 |
|
MOS |
0.04% of diet (400 mg/kg) |
Pathogen exclusion, FCR, BWG |
MDPI Agriculture, 2025 |
|
MOS + Beta-glucan (combined) |
1.0 g/kg total |
Best FCR, highest feed intake, gut integrity |
World Vet Journal, 2024 |
Note: Both Spirulina’s phycocyanin and yeast’s beta glucans are known to be adversely affected by high-temperature pelleting; low-temperature processing or coated/encapsulated forms are recommended.
Frequently Asked Questions
Q: Can we use Spirulina and bio-actives from yeast in the same feed program?
A: Yes, because they are not similar but complementary. Spirulina acts on antioxidant status, gut microbiota, and cytokine level immunity. Beta-glucan acts on macrophage response. MOS acts physically to prevent pathogens.
Q: Are these supplements effective as natural alternatives to antibiotics in broilers?
A: Peer-reviewed studies confirm that MOS, beta-glucan, and Spirulina, alone and in combination, are effective in broilers to achieve growth and health results similar to those with antibiotic growth promoters but without residues or resistance.
Q: At what stage in broiler production should we introduce these supplements?
A: As early as in the starter phase (1 to 14 days). The most important period in which immune priming and gut microbiota formation play a major role is in the first two weeks of life. This is where both bio-actives from yeast and Spirulina give us the highest return on investment.
Q: Do bio-actives from yeast enhance egg quality in layers?
A: Yes. Supplementing layers with MOS and beta-glucan was shown to enhance feed efficiency, strength of immune response, and egg production in layers in several studies reviewed in MDPI Agriculture (2025).
The Bottom Line
Spirulina and yeast bioactives are the cutting edge in next-generation poultry nutrition, not in competition with each other, but in combination to form a biological system. The combination offers what no single product can: antioxidant protection, educated innate immunity, exclusion of pathogens, balance of intestinal microbes, and superior growth promotion, all without antibiotics.
This combination is now the new standard in a post-antibiotic production environment.
